Insulated gate field effect transistors (IGFETs) are much used in modern electronics as individual devices and as part of various integrated circuits (ICs). Metal-oxide-semiconductor (MOS) devices are a well-known form of IGFETs and are commonly referred to by the abbreviation MOSFET. The abbreviations MOS and MOSFET and the terms for which they stand are commonly used in the art to refer to IGFETs irrespective of whether the conductive gate of such devices is metallic or of some other conductor, and irrespective of whether the gate insulator is of oxide or some other dielectric. Unless specifically noted otherwise, the abbreviations MOS, MOSFET and the terms for which they stand are to be interpreted to include any conductive material and not just metallic elements for the gate conductor and any dielectric material and not just oxides for the gate insulator.
Laterally-diffused-metal-oxide-semiconductor (LDMOS) devices are a well-known sub-set of MOSFETs that are much used, especially in connection with high voltage and/or high power applications. Various modifications have been made to LDMOS devices to improve their various properties, e.g., breakdown voltage, gain, leakage current, power handling capability, etc. Nevertheless, there is an ongoing need for further improvements. This is especially true in connection with the source-drain breakdown voltage (referred to as “BVDSS”) of LDMOS devices. The various embodiments of the invention illustrated herein provide devices of improved properties.